彼は仕事に熱心だ。
He is enthusiastic about his work.
学生たちは先生の話を熱心に聞いていた。
The students were listening intently to what the teacher was saying.
彼女は熱心な読書家で、月に二十冊は本を読む。
She is an avid reader and gets through at least twenty books a month.
あまりの熱心さに負けて、ついに入部を認めた。
Won over by his sheer eagerness, I finally let him join the club.